The adjusting mining technology of combining fully mechanized with individual prop,rotating,hilt,irregular form,and double unit face on thin coal seam of Tianchen Mine

Analyzed the situations and characteristics of thin coal seam mining and its mining technologies,and introduced the mining innovation technology used by Tianchen Coal Mine of Zhaozhuang Coal Company of China.This innovation technology combined the fully mechanized mining with individual props,and the working face of mining is over length,irregular form and double units.The rotational adjusting mining technology on thin coal seam is also practiced in this new mining technology.The detail technologies,such as outlays of working face and ways,mining methods,equipments of cutting,transporting and sporting,have been introduced.So that,using the synthetic and creative mining tech- nologies,Tianchen Coal Mine solves the mining problems of thin coal seam successfully.

Back-and-forth mining for hard and thick coal seams—research about the mining technology for fully mechanized caving working face of Datong Mine

The article introduced the key technology, mining process, and back-and-forth mining method for the caving working face of hard-thick coal seams in Datong mine, and researched this innovations process, optimized the systemic design and working face out-play, tried to perfect the caving mining technology of hard-thick coal seams further.

Prediction of face advance rate and determination of the operation efficiency in retreat longwall mining panel using rock engineering system

A new approach for prediction of face advance rete (FAR) prior to mining operation and determination of the operation efficiency after mining operation in retreat longwall mining panel is presented based upon the concepts of rock engineering system (RES). For this purpose, six longwall panels considered in Parvadeh-I coal mine. Seven major effective parameters on FAR was selected including coal mine roof rating, gas propagation, safety factor of longwall face, ratio of joint spacing to cutting depth at longwall face, longwall face inclination, panel width, floor rock mass rating. To performance evaluation of the presented model, the relationship between the average vulnerability indexes of advance operation with FAR was determined in considered panels with coefficient of determination (R2) equal to 0.884 that indicate relatively acceptable correlation and compatibility. Investigations of the research indicated that it is possible to determine the actual operation efficiency under fair conditions by a RES-based model. The inevitable reduction of FAR for each longwall panel was determined by presented model that the difference amount between the maximum possible practical face advance rate (FARmpp) and recorded actual face advance rate (FARa) indicate the operation efficiency. Applied approach in this paper can be used to prediction of FAR in retreat longwall mining panel for same conditions that can have many benefits, including better and more accurate planning for the sales market and mine operation. Also, presented method in this paper can be applied as a useful tool to determination of actual operation efficiency for other sections and extraction methods in coal mines.

Suitable retention and recovery technology of floor coal at ends of fully mechanized face with great mining heights

Gateways at faces of great mining heights are mostly driven along the roof of coal seams.For gateway height restrictions,a 1-3 m floor coal is retained,leaving a triangular floor coal at the face ends,causing a loss of coal.In order to improve coal recovery rates and to ensure efficiency of equipment at coal mining faces,we investigated suitable retention methods and recovery technology of floor coal at face ends.The upper floor coal can directly be recovered by a shearer with floor dinting.The lower floor coal is recovered by shearer with floor dinting after advanced floor dinting and retaining a step for protecting coal sides in a haulage gateway.Field practice shows that this method can improve the coal recovery rates at fully mechanized working faces with great mining heights.

Ground pressure and overlying strata structure for a repeated mining face of residual coal after room and pillar mining

To investigate the abnormal ground pressures and roof control problem in fully mechanized repeated mining of residual coal after room and pillar mining, the roof fracture structural model and mechanical model were developed using numerical simulation and theoretical analysis. The roof fracture characteristics of a repeated mining face were revealed and the ground pressure law and roof supporting condi- tions of the repeated mining face were obtained. The results indicate that when the repeated mining face passes the residual pillars, the sudden instability causes fracturing in the main roof above the old goal and forms an extra-large rock block above the mining face. A relatively stable ＂Voussoir beam＂ structure is formed after the advance fracturing of the main roof. When the repeated mining face passes the old goaf, as the large rock block revolves and touches gangue, the rock block will break secondarily under overburden rock loads. An example calculation was performed involving an integrated mine in Shanxi province, results showed that minimum working resistance values of support determined to be reason- able were respectively 11,412 kN and 10,743 kN when repeated mining face passed through residual pillar and goaf. On-site ground pressure monitoring results indicated that the mechanical model and support resistance calculation were reasonable.

Primary study on the ＂θ＂ letter type overlying multi-strata spatial structure of mining face surrounded by mined areas

The overlying strata spatial structure academic viewpoint thinks the primary factor which controls the stope presses is the overlying strata spatial structure movement; the spatial structure above the later period coal pillar surrounded by mined areas is the most complex overlying strata spatial structure and study on its evolution law has the important realistic project significance for strata movement control and production safety. The existing research results indicate that the special structure of the first working face of the mine begins to develop lengthways from stratum movement above mined areas and extends level in the exploitation direction. From existing overlying strata spatial structure fundamental research achievement, the spatial structure above the later period coal column surrounded by mined areas have following characteristic： The spatial structure formation is from the top to the lower and from large to small. According to the findings, a formula with the use of rock layer migration angle delta was put forward to estimate isolated island coal column width on which different stratum structure is gonging to form.

Systematic principles of surrounding rock control in longwall mining within thick coal seams

Effective surrounding rock control is a prerequisite for realizing safe mining in underground coal mines.In the past three decades, longwall top-coal caving mining(LTCC) and single pass large height longwall mining(SPLL) found expanded usage in extracting thick coal seams in China. The two mining methods lead to large void space left behind the working face, which increases the difficulty in ground control.Longwall face failure is a common problem in both LTCC and SPLL mining. Such failure is conventionally attributed to low strength and high fracture intensity of the coal seam. However, the stiffness of main components included in the surrounding rock system also greatly influences longwall face stability.Correspondingly, surrounding rock system is developed for LTCC and SPLL faces in this paper. The conditions for simultaneous balance of roof structure and longwall face are put forward by taking the stiffness of coal seam, roof strata and hydraulic support into account. The safety factor of the longwall face is defined as the ratio between the ultimate bearing capacity and actual load imposed on the coal wall.The influences provided by coal strength, coal stiffness, roof stiffness, and hydraulic support stiffness,as well as the movement of roof structure are analyzed. Finally, the key elements dominating longwall face stability are identified for improving surrounding rock control effectiveness in LTCC and SPLL faces.

The Recent Technological Development of Intelligent Mining in China

In the last five years, China has seen the technological development of intelligent mining and the application of the longwall automation technology developed by the Longwall Automation Steering Committee. This paper summarizes this great achievement, which occurred during the 12th Five-Year Plan （2011-2015）, and which included the development of a set of intelligent equipment for hydraulic-powered supports, information transfers, dynamic decision-making, performance coordination, and the achievement of a high level of reliability despite difficult conditions. Within China, the intelligent system of a set of hydraulic-powered supports was completed, with our own intellectual property rights. An intelligent mining model was developed that permitted unmanned operation and single-person inspection on the work face. With these technologies, the number of miners on the work face can now be significantly reduced. Miners are only required to monitor mining machines on the roadway or at the surface control center, since intelligent mining can be applied to extract middle-thick or thick coal seams. As a result, miners＇ safety has been improved. Finally, this Darter discusses theprospects and challenges of intelligent mining over the next ten years.

Mating model on production capacity for the system of cutting coal and drawing top-coal in FMMSC

Being a safe and highly-efficient mining method, fully mechanized mining with sublevel caving （FMMSC） was extensively employed in Chinese coal mines with thick seam. In order to make drawing top-coal furthest to parallel work with shearer cutting coal, decrease failure ratio of rear scraper conveyor and increase safe production capacity of equipments, based on production technology, set up the mating model of safe production capacity of equipments for the system of drawing top-coal and shearer cutting coal in coal face with sublevel caving. It is mean capability of drawing top-coal adapted to the capability of shearer cutting coal in a working circle in the coal face that was deduced. The type selection of equipment of rear scraper conveyor can be tackled with this mating model. The model was applied in FMMSC in Yangcun Coal Mine, Yima Coal Group of China. With the mating light-equipments, the coal output in coal face attained 1.05 Mt in 2004. It gained better technical-economic benefit.

Surrounding Rock Failure Mechanism and Control Technology of Gob-Side Entry with Triangle Coal Pillar at Island Longwall Panel in 15 m Extra-Thick Coal Seams

Taking the return air roadway of Tashan 8204 isolated island working face as the background, the evolution law of the stress field in the surrounding rock of the widened coal pillar area roadway during the mining period of the isolated island working face is obtained through numerical simulation. The hazardous area of strong mine pressure under different coal pillar widths is determined. Through simulation, it is known that when the width of the coal pillar is less than 20 m, there is large bearing capacity on the coal side of the roadway entity. The force on the side of the coal pillar is relatively small. When the width of the coal pillar ranges from 25 m to 45 m, the vertical stress on the roadway and surrounding areas is relatively high. Pressure relief measures need to be taken during mining to reduce surrounding rock stress. When the width of the coal pillar is greater than 45 m, the peak stress of the coal pillar is located in the deep part of the surrounding rock, but it still has a certain impact on the roadway. It is necessary to take pressure relief measures to transfer the stress to a deeper depth to ensure the stability of the triangular coal pillar during the safe mining period of the working face. This provides guidance for ensuring the stability of the triangular coal pillar during the safe mining period of the working face.

Prevention of gob ignitions and explosions in longwall mining using dynamic seals

Most, if not all longwall gob areas accumulate explosive methane-air mixtures that pose a deadly hazard to miners. Numerous mine explosions have originated from explosive gas zones(EGZs) in the longwall gob. Since 2010, researchers at the Colorado School of Mines(CSM) have studied EGZ formation in longwall gobs under two long-term research projects funded by the National Institute for Occupational Safety and Health. Researchers used computational fluid dynamics along with in-mine measurements. For the first time, they demonstrated that EGZs form along the fringe areas between the methane-rich atmospheres and the fresh air ventilated areas along the working face and present an explosion and fire hazard to mine workers. In this study, researchers found that, for progressively sealed gobs, a targeted injection of nitrogen from the headgate and tailgate, along with a back return ventilation arrangement, will create a dynamic seal of nitrogen that effectively separates the methane zone from the face air and eliminates the EGZs to prevent explosions. Using this form of nitrogen injection to create dynamic seals should be a consideration for all longwall operators.

Waste-filling in fully-mechanized coal mining and its application

A fully-mechanized coal mining (FMCM) technology capable of filling up the goaf with wastes (including solid wastes) is described. Industrial tests have proved that by using this technology not only can waste be re-used but also coal resources can be exploited with a higher recovery rate without removing buildings located over the working faces. Two special devices, a hydraulic support and a scraper conveyor, run side-by-side on the same working face to simultaneously realize mining and filling. These are described in detail. The tests allow analysis of rock pressure and ground subsidence when backfilling techniques are employed. These values are compared to those from mining without using backfilling techniques, under the same geological conditions. The concept of equivalent mining height is proposed based on theoretical analysis of rock pressure and ground subsidence. The upper limits of the rock pressure and ground subsidence can be estimated in backfilling mining using this concept along with traditional engineering formulae.

In-pit coal mine personnel uniqueness detection technology based on personnel positioning and face recognition

Since the coal mine in-pit personnel positioning system neither can effectively achieve the function to detect the uniqueness of in-pit coal-mine personnel nor can identify and eliminate violations in attendance management such as multiple cards for one person, and swiping one's cards by others in China at present. Therefore, the research introduces a uniqueness detection system and method for in-pit coal-mine personnel integrated into the in-pit coal mine personnel positioning system, establishing a system mode based on face recognition + recognition of personnel positioning card + release by automatic detection. Aiming at the facts that the in-pit personnel are wearing helmets and faces are prone to be stained during the face recognition, the study proposes the ideas that pre-process face images using the 2D-wavelet-transformation-based Mallat algorithm and extracts three face features: miner light, eyes and mouths, using the generalized symmetry transformation-based algorithm. This research carried out test with 40 clean face images with no helmets and 40 lightly-stained face images, and then compared with results with the one using the face feature extraction method based on grey-scale transformation and edge detection. The results show that the method described in the paper can detect accurately face features in the above-mentioned two cases, and the accuracy to detect face features is 97.5% in the case of wearing helmets and lightly-stained faces.

Research on Feasibility of Top-Coal Caving Based on Neural Network Technique

Based on the neural network technique, this paper proposes a BP neural network model which integrates geological factors which affect top coal caving in a comprehensive index. The index of top coal caving may be used to forecast the mining cost of working faces, which shows the model’s potential prospect of applications.

汇能集团智能化综采工作面建设创新及实践

煤矿智能化建设是实现煤炭企业转型升级和高质量发展的核心技术支撑,也是实现企业减人增效的重要途径。针对汇能集团智能化建设存在的问题,在管理模式和技术创新方面总结了企业在智能化建设过程中的经验。以宝平湾煤矿4115工作面智能化建设为例,针对周期性来压大,顶板破碎、片帮等问题,通过智能化跟机技术、液压支架姿态监测、液压支架护帮板防撞和智能控制等关键技术进行创新,最终实现了工作面3人常态化生产,设备自动化开机率大于95%,实现了安全高效生产,可为相似地质条件下的工作面智能化建设提供一定参考。

基于GRA-TOPSIS的综采工作面异常来压预警研究

为了预防开采期间工作面矿压显现明显,局部地段甚至异常来压诱发的压架等问题。通过数理分析,建立的工作面异常来压评价模型对矿井中异常来压起到防范预警作用,其研究成果主要如下:(1)通过分析国内矿井的异常来压情况,选取埋深、采高煤厚比、煤层倾角、基本顶厚度、直接顶厚度、推进速度、倾向长度等作为工作面来压评价因素,构建异常来压评价体系。(2)利用熵权法处理矿区数据得出各个因素的权重值,由TOPSIS法通过加权矩阵进行得分排序,采用灰色关联度分析法对TOPSIS法进行改进优化,得出灰色关联权重矩阵,进行构建工作面异常来压评价模型。(3)将所提出的模型应用在察哈素煤矿中,其评价效果较为理想。

临近煤矿工作面油气井泄漏监测方法研究

为了研究煤矿工作面附近油气井泄漏情况,采用对比分析法,在煤矿工作面附近的油气井、井下工作面附近巷道和采空区中采集了一定量的气体样品,进行了气体组分研究和碳同位素分析研究。研究表明,在试验区域,通过气体组分难以判断油气井是否向煤矿工作面发生泄漏;甲烷碳同位素值测定方法为临近煤矿工作面的油气井泄漏监测的有效技术。

袁大滩煤矿主斜井带式输送机提能改造设计

以袁大滩煤矿主斜井带式输送机为例,介绍了主斜井带式输送机提能改造的设计特点:采用低噪声节能托辊和低滚阻节能型输送带来降低运行阻力,采用工期最短的改造方案来减少矿井停产造成的经济损失。改造的思路和方案,可供相关煤矿和设计人员参考借鉴。

基于FaceNet的煤矿人员考勤识别

煤矿人员出入井考勤系统的准确性不仅是煤矿安全的必要保障,而且也可为突发事故的及时救援提供考量依据。通过传统的考勤模式加上生物特征识别可有效提高煤矿人员出入井识别效率。针对煤矿生产环境中存在煤尘、粉尘污染人员面部等问题,采用MTCNN人脸检测方法对煤矿人员出入井进行人脸检测,并结合FaceNet人脸识别方法识别出入井人员信息。经实验表明,该方法可有效、实时地监控人员考勤,避免了一人多卡等违规现象。

高温采煤工作面全风流路径风温及冷负荷预测方法研究

为改善井下工作环境,打破高温矿井逢夏停工停产的困境,以平煤股份十矿为工程背景,提出了基于全风流路径风温预测的采煤工作面冷负荷计算方法。建立了采煤工作面温度场数值模型,分析了入口风温与控温靶区温度值的依变关系;设置控温靶区目标温度值,并通过焓差法对制冷前后的采煤工作面冷负荷进行计算。研究结果表明,以采煤工作面上端头超前工作面50 m为控温靶区,入口温度与控温靶区温度的依变关系为:y=89.57-72.88×0.99^(x);降温前,入口风温为30℃,控温靶区温度为35.7℃。降温后,入口风温为13.6℃,控温靶区温度为26℃;降温前工作面入口风流焓值为85.53 kJ/kg,控温靶区风流焓值为128.88 kJ/kg;降温后工作面入口风流焓值为28.36 kJ/kg,控温靶区风流焓值为66.77 kJ/kg。工作面的冷负荷为2286.8 kW。制冷机组制冷量为2300 kW,机组运行后工作面温度平均降低7~10℃,湿度降低20%以上,降温除湿效果明显。